N-acetylcysteine for adults with acute respiratory distress syndrome: A meta-analysis of randomized controlled trials

Background: Acute respiratory distress syndrome is regarded as a formidable clinical challenge due to its high prevalence and mortality. The treatment of acute respiratory distress syndrome is very complex and difficult. As an adjuvant therapy, the antioxidant N-acetylcysteine has been investigated for several years but the benefit is controversial. Objectives: We performed the systematic review and meta-analysis of randomized controlled trials to evaluate the efficacy of N-acetylcysteine on patients with acute respiratory distress syndrome. Methods: We searched PubMed, CENTRAL, and CBM databases. Randomized controlled trials comparing the effects of N-acetylcysteine and control were included. Overall mortality was the primary outcome; length of intensive care unit stay, duration of mechanical ventilation, glutathione levels, and PaO 2 /FiO 2 were the secondary outcomes. Results: Eight trials with a total of 289 patients were included. Compared to the control group, the N-acetylcysteine group did not lower the overall mortality (risk ratio: 0.83; 95% confidence interval: 0.62 to 1.11; P = 0.21; I 2 = 0%). However, N-acetylcysteine significantly shortened intensive care unit stay in the random-effects model (mean difference: –4.47 days; 95% confidence interval: –8.79 to −0.14; P = 0.04; I 2 = 46%). Due to substantial heterogeneity and limited number of studies, the data of duration of mechanical ventilation, glutathione levels, and PaO 2 /FiO 2 could not be pooled in the meta-analysis. Conclusion: N-acetylcysteine is ineffective in reducing mortality but beneficial for intensive care unit stay. Nonetheless, the effectiveness of N-acetylcysteine for acute respiratory distress syndrome is limited and further research is required before strong recommendations can be made.